<div>The pyrolysis-reflectance tie database table contains publicly available results from Geoscience Australia's organic geochemistry (ORGCHEM) schema and supporting oracle databases, which combine key properties related to thermal maturity. These data are typically used as input parameters in basin analysis and petroleum systems modelling to assist with the discovery and evaluation of sediment-hosted energy resources. The programmed pyrolysis analyses and the maceral reflectance analyses undertaken using reflected light microscopy are conducted on rock samples, either as cores, cuttings or rock chips, taken from boreholes and field sites in Australian sedimentary basins. The full datasets are available in the pyrolysis, vitrinite reflectance, maceral reflectance and organoclast maturity web services. These analyses are performed by various laboratories in service and exploration companies, Australian government institutions and universities using a range of instruments.</div><div><br></div><div>These data are collated from destructive analysis reports (DARs), well completion reports (WCRs), and literature. The data are delivered in the Combined Pyrolysis and Vitrinite Reflectance web services on the Geoscience Australia Data Discovery Portal at https://portal.ga.gov.au which will be periodically updated.</div>

<div><strong>Output Type: </strong>Exploring for the Future Extended Abstract</div><div><br></div><div><strong>Short Abstract: </strong>Groundwater geochemistry is an important and often under-appreciated medium to understand geology below surface and is a valuable tool as part of a regional mineral exploration program. This study presents an assessment of hydrogeochemical results from the Curnamona and Mundi region with respect to their insights into mineral prospectivity and characterisation of groundwater baselines. The work is a collaboration with the Mineral Exploration Cooperative Research Centre (MinEx CRC), the Geological Survey of New South Wales and the Geological Survey of South Australia as part of Geoscience Australia’s Exploring for the Future program. It combines new and legacy groundwater chemistry from 297 samples to identify multiple elevated multi-element anomalies (Ag, Pb, Cd) and signatures of sulfide mineralisation (d34S and sulfur excess), which are interpreted as potential features from subsurface Broken Hill Type mineralisation (Pb-Zn-Ag). Additional multi-element anomalies (Cu, Mo, Co, Au) may be attributable to Cu-Au, Cu-Mo and Au mineralisation. We then apply hierarchical cluster analysis to understand sample hydrostratigraphy and characterise robust hydrogeochemical baselines for the major aquifer systems in the region. This reveals that the majority of anomalies are restricted to groundwaters derived from basement fractured rock aquifer systems, with a couple anomalies observed in the Lake Eyre Basin cover, which helps narrow the search-space for future groundwater-based mineral exploration in this region (to prioritise these aquifers and anomalies). In addition, we demonstrate the capability of these local hydrogeochemical baselines to support more sensitive resolution of hydrogeochemical anomalies relating to mineralisation, as well as reveal hydrogeological processes such as mixing.</div><div><br></div><div><strong>Citation: </strong>Reid, N., Schroder, I., Thorne, R., Folkes, C., Hore, S., Eastlake, M., Petts, A., Evans, T., Fabris, A., Pinchand, T., Henne A., & Palombi, B.R., 2024. Hydrogeochemistry of the Curnamona and Mundi region. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts. Geoscience Australia, Canberra. https://doi.org/10.26186/149509</div>

<div>Strontium isotopes (87Sr/86Sr) are useful in the earth sciences (e.g. recognising geological provinces, studying geological processes) as well in archaeological (e.g. informing on past human migrations), palaeontological/ecological (e.g. investigating extinct and extant taxa’s dietary range and migrations) and forensic (e.g. validating the origin of drinks and foodstuffs) sciences. Recently, Geoscience Australia and the University of Wollongong have teamed up to determine 87Sr/86Sr ratios in fluvial sediments selected mostly from the low-density National Geochemical Survey of Australia (www.ga.gov.au/ngsa), with a few additional Northern Australia Geochemical Survey infill samples. The present study targeted the northern parts of Western Australia, the Northern Territory and Queensland in Australia, north of 21.5 °S. The samples were taken mostly from a depth of ~60-80 cm depth in floodplain deposits at or near the outlet of large catchments (drainage basins). A coarse grain-size fraction (&lt;2 mm) was air-dried, sieved, milled then digested (hydrofluoric acid + nitric acid followed by aqua regia) to release total strontium. Preliminary results demonstrate a wide range of strontium isotopic values (0.7048 &lt; 87Sr/86Sr &lt; 1.0330) over the survey area, reflecting a large diversity of source rock lithologies, geological processes and bedrock ages. Spatial distribution of 87Sr/86Sr shows coherent (multi-point anomalies and smooth gradients), large-scale (&gt;100 km) patterns that appears to be consistent, in many places, with surface geology, regolith/soil type and/or nearby outcropping bedrock. For instance, the extensive black clay soils of the Barkly Tableland define a &gt;500 km-long northwest-southeast-trending low anomaly (87Sr/86Sr &lt; 0.7182). Where carbonate or mafic igneous rocks dominate, a low to moderate strontium isotope signature is observed. In proximity to the outcropping Proterozoic metamorphic provinces of the Tennant, McArthur, Murphy and Mount Isa geological regions, conversely, high 87Sr/86Sr values (&gt; 0.7655) are observed. A potential link between mineralisation and elevated 87Sr/86Sr values in these regions needs to be investigated in greater detail. Our results to-date indicate that incorporating soil/regolith strontium isotopes in regional, exploratory geoscience investigations can help identify basement rock types under (shallow) cover, constrain surface processes (e.g. weathering, dispersion), and, potentially, recognise components of mineral systems. Furthermore, the resulting strontium isoscape and model derived therefrom can also be utilised in archaeological, paleontological and ecological studies that aim to investigate past and modern animal (including humans) dietary habits and migrations. &nbsp;The new spatial dataset is publicly available through the Geoscience Australia portal https://portal.ga.gov.au/.</div>

<div>Strontium isotopes (87Sr/86Sr) are useful to trace processes in the Earth sciences as well as in forensic, archaeological, palaeontological, and ecological sciences. As very few large-scale Sr isoscapes exist in Australia, we have identified an opportunity to determine 87Sr/86Sr ratios on archived fluvial sediment samples from the low-density National Geochemical Survey of Australia (www.ga.gov.au/ngsa; last access: 15 December 2022). The present study targeted the northern parts of Western Australia, the Northern Territory and Queensland, north of 21.5 °S. The samples were taken mostly from a depth of ~60-80 cm in floodplain deposits at or near the outlet of large catchments (drainage basins). A coarse (< 2 mm) grain-size fraction was air-dried, sieved, milled then digested (hydrofluoric acid + nitric acid followed by aqua regia) to release <em>total</em> Sr. The Sr was then separated by chromatography and the 87Sr/86Sr ratio determined by multicollector-inductively coupled plasma mass spectrometry. Results demonstrate a wide range of Sr isotopic values (0.7048 to 1.0330) over the survey area, reflecting a large diversity of source rock lithologies, geological processes and bedrock ages. Spatial distribution of 87Sr/86Sr shows coherent (multi-point anomalies and smooth gradients), large-scale (> 100 km) patterns that appear to be broadly consistent with surface geology, regolith/soil type, and/or nearby outcropping bedrock. For instance, the extensive black clay soils of the Barkly Tableland define a > 500 km-long northwest-southeast-trending unradiogenic anomaly (87Sr/86Sr < 0.7182). Where sedimentary carbonate or mafic/ultramafic igneous rocks dominate, low to moderate 87Sr/86Sr values are generally recorded (medians of 0.7387 and 0.7422, respectively). In proximity to the outcropping Proterozoic metamorphic basement of the Tennant, McArthur, Murphy and Mount Isa geological regions, conversely, radiogenic 87Sr/86Sr values (> 0.7655) are observed. A potential correlation between mineralisation and elevated 87Sr/86Sr values in these regions needs to be investigated in greater detail. Our results to-date indicate that incorporating soil/regolith Sr isotopes in regional, exploratory geoscience investigations can help identify basement rock types under (shallow) cover, constrain surface processes (e.g. weathering, dispersion), and, potentially, recognise components of mineral systems. Furthermore, the resulting Sr isoscape and future models derived therefrom can also be utilised in forensic, archaeological, paleontological and ecological studies that aim to investigate, e.g., past and modern animal (including humans) dietary habits and migrations. The new spatial Sr isotope dataset for the northern Australia region is publicly available (de Caritat et al., 2022a; https://dx.doi.org/10.26186/147473; last access: 15 December 2022).</div> <b>Citation:</b> de Caritat, P., Dosseto, A., and Dux, F.: A strontium isoscape of northern Australia, <i>Earth Syst. Sci. Data</i>, 15, 1655–1673, https://doi.org/10.5194/essd-15-1655-2023, <b>2023</b>.

<div>The Petroleum Systems Summary database stores the compilation of the current understanding of petroleum systems information by basin across Australia. The Petroleum Systems Summary database and delivery tool provide high-level information of the current understanding of key petroleum systems for areas of interest. For example, geological studies in the Exploring for the Future (EFTF) program have included the Canning, McArthur and South Nicholson basins (Carr et al., 2016; Hashimoto et al., 2018). The database and tool aim to assist geological studies by summarising and interpreting key datasets related to conventional and unconventional hydrocarbon exploration. Each petroleum systems summary includes a synopsis of the basin and key figures detailing the basin outline, major structural components, data availability, petroleum systems events chart and stratigraphy, and a précis of the key elements of source, reservoir and seal. Standardisation of petroleum systems nomenclature establishes a framework for each basin after Bradshaw (1993) and Bradshaw et al. (1994), with the source-reservoir naming conventions adopted from Magoon and Dow (1994).&nbsp;</div><div><br></div><div>The resource is accessible via the Geoscience Australia Portal&nbsp;(https://portal.ga.gov.au/) via the Petroleum Systems Summary Tool (Edwards et al., 2020).</div>

<div><strong>Output type: </strong>Exploring for the Future Extended Abstract</div><div><br></div><div><strong>Short abstract: </strong>Australian sediment-hosted mineral systems play a crucial role in providing base metals and critical minerals essential for the global low-carbon economy. The Georgina Basin has the key components for forming and preserving a sediment-hosted Zn-Pb mineral system, but historically has been considered ‘cover’ to deeper, more prospective Proterozoic basement rocks. Thus, the basin has remained relatively under-explored, with many questions yet to be resolved on its sediment-hosted Zn-Pb mineral system and prospectivity for Zn-Pb. Utilising new whole-rock and isotope geochemistry of the Georgina Basin from recently drilled holes in the Northern Territory, we demonstrate the sensitivity of local redox boundaries to detect regional mineralisation. Two geochemically enriched zones have been identified and interpreted as redox interfaces which have trapped and concentrated metals from the surrounding basin, a ‘supergene zone’ and a ‘water intercept zone’. The ‘supergene zone’ is a paleo water table horizon, while the ‘water intercept zone’ is an active redox front at the uppermost part of the Cambrian Limestone Aquifer. The enrichment of these redox zones is consistent across multiple drill holes, reaching up to 395 ppm Pb and 1550 ppm Zn. Additionally, the Pb isotopes of high-Pb and sulfidic intervals have a highly radiogenic character (206Pb/204Pb ~22.0–23.0) that is diagnostic of Georgina Basin’s Mississippi Valley-type Zn-Pb mineralisation. Taken together, these results suggest there may be buried mineralisation in this part of the Georgina Basin, as well as highlight the potential of these redox interfaces as a regional reconnaissance target for exploration.</div><div><br></div><div><strong>Citation: </strong>Schroder I.F., Huston D. & de Caritat P., 2024. The geochemistry of redox interfaces for insights into Zn-Pb prospectivity in the Georgina Basin. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://doi.org/10.26186/149116 </div>

<div>This guide and template details data requirements for submission of mineral deposit geochemical data to the Critical Minerals in Ores (CMiO) database, hosted by Geoscience Australia, in partnership with the United States Geological Survey and the Geological Survey of Canada. The CMiO database is designed to capture multielement geochemical data from a wide variety of critical mineral-bearing deposits around the world. Samples included within this database must be well-characterized and come from localities that have been sufficiently studied to have a reasonable constraint on their deposit type and environment of formation. As such, only samples analysed by modern geochemical methods, and with certain minimum metadata attribution, can be accepted. Data that is submitted to the CMiO database will also be published via the Geoscience Australia Portal (portal.ga.gov.au) and Critical Minerals Mapping Initiative Portal (https://portal.ga.gov.au/persona/cmmi).&nbsp;</div><div><br></div>

Major oxides provide valuable information about the composition, origin, and properties of rocks and regolith. Analysing major oxides contributes significantly to understanding the nature of geological materials and processes (i.e. physical and chemical weathering) – with potential applications in resource exploration, engineering, environmental assessments, agriculture, and other fields. Traditionally most measurements of oxide concentrations are obtained by laboratory assay, often using X-ray fluorescence, on rock or regolith samples. To expand beyond the point measurements of the geochemical data, we have used a machine learning approach to produce seamless national scale grids for each of the major oxides. This approach builds predictive models by learning relationships between the site measurements of an oxide concentration (sourced from Geoscience Australia’s OZCHEM database and selected sites from state survey databases) and a comprehensive library of covariates (features). These covariates include: terrain derivatives; climate surfaces; geological maps; gamma-ray radiometric, magnetic, and gravity grids; and satellite imagery. This approach is used to derive national predictions for 10 major oxide concentrations at the resolution of the covariates (nominally 80 m). The models include the oxides of silicon (SiO2), aluminium (Al2O3), iron (Fe2O3tot), calcium (CaO), magnesium (MgO), manganese (MnO), potassium (K2O), sodium (Na2O), titanium (TiO2), and phosphorus (P2O5). The grids of oxide concentrations provided include the median of multiple models run as the prediction, and lower and upper (5th and 95th) percentiles as measures of the prediction’s uncertainty. Higher uncertainties correlate with greater spreads of model values. Differences in the features used in the model compared with the full feature space covering the entire continent are captured in the ‘covariate shift’ map. High values in the shift model can indicate higher potential uncertainty or unreliability of the model prediction. Users therefore need to be mindful, when interpreting this dataset, of the uncertainties shown by the 5th-95th percentiles, and high values in the covariate shift map. Details of the modelling approach, model uncertainties and datasets are describe in an attached word document “Model approach uncertainties”. This work is part of Geoscience Australia’s Exploring for the Future program that provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia’s geology and resource potential. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia’s transition to net zero emissions, strong, sustainable resources and agriculture sectors, and economic opportunities and social benefits for Australia’s regional and remote communities. The Exploring for the Future program, which commenced in 2016, is an eight year, $225m investment by the Australian Government. These data are published with the permission of the CEO, Geoscience Australia.

<div>The soil gas database table contains publicly available results from Geoscience Australia's organic geochemistry (ORGCHEM) schema and supporting oracle databases for gas analyses undertaken by Geoscience Australia's laboratory on soil samples taken from shallow (down to 1 m below the surface) percussion holes. Data includes the percussion hole field site location, sample depth, analytical methods and other relevant metadata, as well as the molecular and isotopic compositions of the soil gas with air included in the reported results. Acquisition of the molecular compounds are by gas chromatography (GC) and the isotopic ratios by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The concentrations of argon (Ar), carbon dioxide (CO₂), nitrogen (N₂) and oxygen (O₂) are given in mole percent (mol%). The concentrations of carbon monoxide (CO), helium (He), hydrogen (H₂) and methane (C₁, CH₄) are given in parts per million (ppm). Compound concentrations that are below detection limit (BDL) are reported as the value -99999. The stable carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) isotopic ratios are presented in parts per mil (‰) and in delta notation as δ¹³C and δ¹⁵N, respectively.</div><div><br></div><div>Determining the individual sources and migration pathways of the components of natural gases found in the near surface are useful in basin analysis with derived information being used to support exploration for energy resources (petroleum and hydrogen) and helium in Australian provinces. These data are collated from Geoscience Australia records with the results being delivered in the Soil Gas web services on the Geoscience Australia Data Discovery portal at https://portal.ga.gov.au which will be periodically updated.</div>

<div>The bulk oils database table contains publicly available results from Geoscience Australia's organic geochemistry (ORGCHEM) schema and supporting oracle databases for the bulk properties of petroleum liquids (e.g., condensate, crude oil, bitumen) sampled from boreholes and field sites. The analyses are performed by various laboratories in service and exploration companies, Australian government institutions, and universities using a range of instruments. Petroleum is composed primarily of hydrocarbons (carbon and hydrogen) with minor quantities of heterocyclic compounds containing either nitrogen, oxygen or sulfur. Data includes the borehole or field site location, sample depth, shows and tests, stratigraphy, analytical methods, other relevant metadata, and various data types including; API gravity, elemental composition and photographs of the samples. The stable carbon (¹³C/¹²C) and hydrogen (²H/¹H) isotopic ratios of crude oil and derivative saturated and aromatic hydrocarbon fractions are presented in parts per mil (‰) and in delta notation as &delta;¹³C and &delta;²H, respectively. Results are also included from methods that separate crude oils into bulk components, such as the quantification of saturated hydrocarbon, aromatic hydrocarbon, resin, and asphaltene (SARA) fractions according to their polarity.</div><div><br></div><div>These data provide information about the petroleum fluid’s composition, source, thermal maturity, secondary alteration, and fluid migration pathways. They are also useful for enhanced oil recovery assessments, petroleum systems mapping and basin modelling. Hence, these sample-based datasets are used for the discovery and evaluation of sediment-hosted resources. Some data are generated in Geoscience Australia’s laboratory and released in Geoscience Australia records. Data are also collated from destructive analysis reports (DARs), well completion reports (WCRs), and literature. The bulk oils data are delivered in the Petroleum Bulk Properties and Stable Isotopes web services on the Geoscience Australia Data Discovery Portal at https://portal.ga.gov.au which will be periodically updated.</div>